A method and apparatus for detecting catheter contact status

Abstract

This invention discloses a method and apparatus for detecting the adhesion status of a catheter. The method includes: measuring a first impedance value, where the first impedance value is the impedance value of each electrode in the catheter; measuring a second impedance value, where the second impedance value is the impedance value between any two electrodes in the catheter; and determining whether the catheter has achieved proper adhesion based on the first impedance value and the second impedance value. This invention determines whether the electrodes are in contact with tissue by measuring the electrode impedance, thereby indicating the overall catheter adhesion status.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and in particular to a method and apparatus for detecting catheter apposition status. Background Technology

[0002] Radiofrequency ablation is a common clinical technique for treating arrhythmias. An interventional catheter is inserted through the vascular system to reach a distal lesion site, and electrical signals are applied to the catheter for diagnosis and treatment. The degree of contact between the catheter and the target tissue has a significant impact on the ablation effect. Good contact not only ensures transmural ablation and improves the ablation effect, but also reduces adverse phenomena such as muscle spasms, thrombosis, and microbubbles during the ablation process.

[0003] A common method for detecting catheter contact involves adding a sensor inside the catheter. When the catheter comes into contact with tissue, the sensor's deformation measures the contact force. However, adding a pressure sensor inside the catheter can cause the catheter tip to become too stiff, making it difficult to pass through tortuous blood vessels and increasing costs. Furthermore, for non-linear catheters, measuring contact force using a pressure sensor is not feasible. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and apparatus for detecting catheter affixation status.

[0005] Specifically, the technical solution of the present invention is as follows:

[0006] This invention provides a method for detecting catheter affixation status, comprising:

[0007] Measure the first impedance value, which is the impedance value of each electrode in the catheter;

[0008] Measure the second impedance value, which is the impedance value between any two electrodes in the catheter;

[0009] Based on the first impedance value and the second impedance value, it is determined whether the catheter has been properly attached.

[0010] In some embodiments, determining whether the catheter has been properly attached based on the first impedance value and the second impedance value includes:

[0011] The electrode with the smallest impedance value is identified as the first electrode, which is the electrode furthest from the tissue.

[0012] Obtain the third impedance value between the first electrode and any other electrode;

[0013] Calculate the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values;

[0014] When the first difference is the largest, the second electrode is selected, which is the electrode closest to the tissue.

[0015] The second electrode is used to determine whether the catheter has been properly attached.

[0016] In some embodiments, determining whether the catheter has been successfully attached based on the second electrode includes:

[0017] If the first impedance value corresponding to the second electrode exceeds the preset impedance value, it is determined that the catheter is in contact with the tissue.

[0018] Determine whether the first impedance value corresponding to the other electrodes exceeds the preset impedance value;

[0019] If the determination is yes, then the entire catheter is successfully attached.

[0020] In some embodiments, determining whether the catheter has been successfully attached based on the second electrode includes:

[0021] Obtain the fourth impedance value between the second electrode and the two adjacent electrodes before the catheter is moved;

[0022] Obtain the fifth impedance value between the second electrode and the two adjacent electrodes after the catheter is moved;

[0023] Calculate the second difference between the fourth impedance value and the corresponding fifth impedance value;

[0024] Obtain the distance the catheter has traveled;

[0025] Calculate the ratio of each of the second differences to the distance traveled;

[0026] If all the ratios are greater than the corresponding preset values, it is determined that the catheter has been successfully attached.

[0027] In some implementations, the first impedance value is calculated according to the following formula:

[0028]

[0029] in, The first impedance value is given by 'a', where 'a' is the weighting factor determined by the distance between the electrode and the target tissue. For blood resistance, This refers to tissue impedance.

[0030] This invention provides a device for detecting catheter affixation status, comprising:

[0031] The first measurement module is used to measure a first impedance value, wherein the first impedance value is the impedance value of each electrode in the catheter;

[0032] The second measurement module is used to measure the second impedance value, which is the impedance value between any two electrodes in the catheter.

[0033] The judgment module is used to determine whether the catheter has been properly attached based on the first impedance value and the second impedance value.

[0034] In some implementations, the determination module includes:

[0035] The first selection submodule is used to determine the electrode with the smallest impedance value as the first electrode, and the first electrode is the electrode farthest from the tissue.

[0036] The acquisition submodule is used to acquire the third impedance value between the first electrode and any other electrode.

[0037] The first calculation submodule is used to calculate the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values;

[0038] The second selection submodule is used to select the second electrode when the first difference is the largest, wherein the second electrode is the electrode closest to the tissue.

[0039] The judgment submodule is used to determine whether the catheter has been properly attached based on the second electrode.

[0040] In some implementations, the determination submodule includes:

[0041] The first comparison unit is used to compare the first impedance value corresponding to the second electrode with a preset impedance value. If the first impedance value corresponding to the second electrode exceeds the preset impedance value, it is determined that the catheter is in contact with the tissue.

[0042] The second comparison unit is used to compare the first impedance value corresponding to other electrodes with the preset impedance value. If the first impedance value corresponding to other electrodes exceeds the preset impedance value, the entire catheter is successfully attached.

[0043] In some implementations, the determination submodule includes:

[0044] The first acquisition unit is used to acquire the fourth impedance value between the second electrode and two adjacent electrodes before the catheter moves;

[0045] The first acquisition unit is further configured to acquire the fifth impedance value between the second electrode and two adjacent electrodes after the catheter is moved;

[0046] The first calculation unit is used to calculate the second difference between the fourth impedance value and the corresponding fifth impedance value;

[0047] The second acquisition unit is used to acquire the travel distance of the catheter;

[0048] The second calculation unit is used to calculate the ratio of each of the second differences to the moving distance;

[0049] In the third comparison unit, if all the ratios are greater than the corresponding preset values, it is determined that the catheter has been successfully attached.

[0050] This invention provides an impedance measurement system for a multi-electrode ablation catheter, comprising a multi-electrode ablation catheter, an impedance measurement device, and a reference electrode, wherein:

[0051] The multi-electrode ablation catheter is connected to the impedance measuring device. The impedance measuring device, the tip electrode of the multi-electrode ablation catheter, the tissue, the blood, and the reference electrode constitute an impedance measuring circuit. The reference electrode is an external electrode patch or an electrode in the middle section of the multi-electrode ablation catheter.

[0052] The impedance measuring device applies a driving signal to the multi-electrode ablation catheter;

[0053] The impedance measuring device uses any of the methods described in the foregoing embodiments to determine the contact status of the multi-electrode ablation catheter.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] This invention measures the electrode impedance and determines whether the electrode is in contact with the tissue based on the measurement results, thereby indicating the overall catheter contact status. For nonlinear catheters, it is not necessary to install a pressure sensor inside the catheter to determine the catheter contact status. Since no sensor is installed inside the catheter, the problem of the catheter tip being too stiff to pass through curved blood vessels can also be avoided. Attached Figure Description

[0056] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of the present invention.

[0057] Figure 1 This is a flowchart of an embodiment of the method for detecting catheter contact status according to the present invention;

[0058] Figure 2 This is a flowchart of another embodiment of the method for detecting catheter contact status of the present invention;

[0059] Figure 3 This is a structural block diagram of an embodiment of the device for detecting catheter contact status of the present invention.

[0060] Explanation of icon numbers:

[0061] First measurement module 100, second measurement module 200, and judgment module 300. Detailed Implementation

[0062] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0064] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0065] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or sets.

[0066] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0067] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0068] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0069] In one embodiment, such as Figure 1 As shown, a method for detecting catheter affixation status includes:

[0070] S100 measures a first impedance value, which is the impedance value of each electrode in the catheter.

[0071] Specifically, the impedance measuring device, the electrode at the catheter tip, the blood, and the external electrode patch form the first impedance measuring circuit. The impedance measuring device sends a constant voltage or constant current, which flows through the catheter to the catheter tip, then through the blood to the body, and finally returns to the impedance measuring circuit through the patch.

[0072] S200 measures a second impedance value, which is the impedance between any two electrodes in the catheter.

[0073] Specifically, the impedance measuring device, the electrode at the catheter tip, the blood, the tissue, and the electrode in the middle section of the catheter form a second impedance measuring circuit. The impedance measuring device sends a constant voltage or constant current, which flows through the catheter to the catheter tip, through the blood and tissue, and finally back into the impedance measuring circuit through the electrode in the middle section of the catheter.

[0074] S300 determines whether the catheter has been properly attached based on the first impedance value and the second impedance value.

[0075] In this embodiment, by measuring the electrode impedance, the system determines whether the electrode is in contact with the tissue based on the measurement results, thereby indicating the overall contact status of the catheter.

[0076] In one embodiment, such as Figure 2 As shown, a method for detecting catheter affixation status includes:

[0077] S100 measures a first impedance value, which is the impedance value of each electrode in the catheter.

[0078] Specifically, the impedance measuring device sends a constant voltage / current to each electrode in the conduit, finally reaching the negative electrode, to measure the impedance value of each electrode in the conduit. , This is the first impedance value.

[0079] S200 measures a second impedance value, which is the impedance between any two electrodes in the catheter.

[0080] Specifically, the impedance measuring device sends a constant voltage / current to each electrode in the conduit, while the other electrodes act as receivers. The impedance value is then measured. This is the second impedance value.

[0081] S310 determines the electrode with the smallest first impedance value as the first electrode, which is the electrode furthest from the tissue.

[0082] Specifically, the first impedance value Forming a matrix In the matrix Find the lowest The lowest value corresponds to the electrode n that is furthest from the tissue, and electrode n is the first electrode.

[0083] S320 obtains the third impedance value between the first electrode and any other electrode.

[0084] Specifically, based on the second impedance value, the third impedance value between electrode n and any other electrode is obtained.

[0085] S330 calculates the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values.

[0086] Specifically, the third impedance value forms a matrix. Calculate the difference between the first impedance value and each of the third impedance values ​​corresponding to electrode m in the matrix; or, from the matrix... Find the nth column, which is the column containing the third impedance value corresponding to electrode n. Calculate the first difference between each third impedance value in this column and the first impedance value corresponding to electrode m.

[0087] When the first difference is the largest, S340 selects the second electrode, which is the electrode closest to the tissue.

[0088] Specifically, when the first difference is the largest, the electrode m corresponding to this difference is the electrode closest to the tissue, and electrode m is selected as the second electrode.

[0089] S351 obtains the fourth impedance value between the second electrode and the two adjacent electrodes before the catheter is moved, and obtains the fifth impedance value between the second electrode and the two adjacent electrodes after the catheter is moved.

[0090] Specifically, the two adjacent electrodes of electrode m are electrode m-1 and electrode m+1, based on the second impedance value. Obtain the impedance value between electrode m and electrode m-1 before catheter movement. The impedance value between electrode m and electrode m+1 Obtain the impedance between electrode m and electrode m-1 after the catheter is moved. The impedance value between electrode m and electrode m+1 .

[0091] S352 calculates the second difference between the fourth impedance value and the corresponding fifth impedance value.

[0092] Specifically, calculation , , , .

[0093] S353 obtains the distance the catheter has traveled.

[0094] S354 calculates the ratio of each of the second differences to the moving distance.

[0095] Specifically, calculation , , , , This represents the distance the catheter travels.

[0096] S355 determines whether the ratio is greater than the corresponding preset value. If the determination is yes, the catheter is successfully attached.

[0097] Specifically, respectively , Compare with preset values ​​A and B, if , Then electrodes m and m-1 are in contact, while electrode m+1 is not in contact; if , Then electrodes m and m+1 are in contact, while electrode m-1 is not in contact; if , Then, electrodes m, m-1, and m+1 are not in contact; if , If electrodes m, m-1, and m+1 are all in contact, then the catheter is considered to be in contact with the tissue.

[0098] In this embodiment, the impedance values ​​of each electrode inside the catheter and the impedance value between any two electrodes inside the catheter are measured. Based on the measurement results, the electrode n that is farthest from the tissue and the electrode m that is closest to the tissue are found. The adhesion status of the catheter is determined based on the impedance value between two adjacent electrodes m before and after the catheter is moved and the distance the catheter is moved.

[0099] In one embodiment, a method for detecting catheter affixation status includes the steps of:

[0100] S100 measures a first impedance value, which is the impedance value of each electrode in the catheter.

[0101] Specifically, the impedance measuring device sends a constant voltage / current to each electrode in the conduit, finally reaching the negative electrode, to measure the impedance value of each electrode in the conduit. , This is the first impedance value.

[0102] The first impedance value can be calculated using the following formula:

[0103]

[0104] in, Here, 'a' represents the first impedance value, and 'a' represents the weighting of the distance between the electrode and the target tissue. For blood resistance, This is the tissue impedance; when the electrode is far from the tissue, i.e., a is 0, the measured impedance is... For blood resistance When the electrode contacts the tissue, i.e., when a is 1, the measured value is... for .

[0105] S200 measures a second impedance value, which is the impedance between any two electrodes in the catheter.

[0106] Specifically, the impedance measuring device sends a constant voltage / current to each electrode in the conduit, while the other electrodes act as receivers. The impedance value is then measured. This is the second impedance value.

[0107] S310 determines the electrode with the smallest first impedance value as the first electrode, which is the electrode furthest from the tissue.

[0108] Specifically, the first impedance value Forming a matrix In the matrix Find the lowest The lowest value corresponds to the electrode furthest from the tissue.

[0109] S320 obtains the third impedance value between the first electrode and any other electrode.

[0110] Specifically, based on the second impedance value The impedance value between the first electrode and any other electrode is obtained as the third impedance value.

[0111] S330 calculates the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values.

[0112] Specifically, the third impedance value forms a matrix. Calculate the difference between the first impedance value corresponding to the first electrode and each of the third impedance values ​​in the matrix; or, from the matrix... Find the nth column, which is the column containing the third impedance value corresponding to the first electrode. Calculate the difference between each third impedance value in this column and the first impedance value corresponding to the first electrode.

[0113] When the first difference is the largest, S340 selects the second electrode, which is the electrode closest to the tissue.

[0114] Specifically, when the first difference is the largest, the electrode corresponding to that difference is the electrode closest to the tissue, and this electrode is selected as the second electrode.

[0115] S356 determines whether the first impedance value corresponding to the second electrode exceeds the preset impedance value. If the determination is yes, then the catheter is confirmed to be in contact with the tissue, and step 351 is executed.

[0116] Specifically, when the negative electrode of the impedance measuring device is outside the patient's body, the range of the first impedance value is 100-300Ω; when the negative electrode of the impedance measuring device is inside the catheter, the range of the first impedance value will not exceed 300Ω.

[0117] S357 determines whether the first impedance value corresponding to other electrodes exceeds the preset impedance value. If the determination is yes, the entire catheter is successfully attached.

[0118] In this embodiment, the impedance values ​​of each electrode inside the catheter and the impedance value between any two electrodes inside the catheter are measured. Based on the measurement results, the electrode farthest from the tissue and the electrode closest to the tissue are found. The impedance values ​​corresponding to these two electrodes are compared with preset impedance values. The adhesion status of the catheter is detected based on the comparison results.

[0119] In one embodiment, such as Figure 3 As shown, a device for detecting catheter contact status includes a first measuring module 100, a second measuring module 200, and a judgment module 300, wherein:

[0120] The first measurement module 100 is used to measure a first impedance value, which is the impedance value of each electrode in the catheter.

[0121] The second measurement module 200 is used to measure a second impedance value, which is the impedance value between any two electrodes in the conduit.

[0122] The judgment module 300 is used to determine whether the catheter has been properly attached based on the first impedance value and the second impedance value.

[0123] In one embodiment, the determining module 300 includes:

[0124] The first selection submodule 310 is used to determine the electrode with the smallest first impedance value as the first electrode, which is the electrode farthest from the tissue.

[0125] The acquisition submodule 320 is used to acquire the third impedance value between the first electrode and any other electrode.

[0126] The first calculation submodule 330 is used to calculate the first difference between the first impedance value corresponding to the first electrode and each third impedance value.

[0127] The second selection submodule 340 is used to select the second electrode when the first difference is the largest. The second electrode is the electrode closest to the tissue.

[0128] The judgment submodule 350 is used to determine whether the catheter has been properly attached based on the second electrode.

[0129] In one embodiment, the determination submodule 350 includes a first comparison unit 351 and a second comparison unit 352, wherein:

[0130] The first comparison unit 351 is used to compare the first impedance value corresponding to the second electrode with a preset impedance value. If the first impedance value corresponding to the second electrode exceeds the preset impedance value, it is determined that the catheter is in contact with the tissue.

[0131] The second comparison unit 352 is used to compare the first impedance value corresponding to other electrodes with the preset impedance value. If the first impedance value corresponding to other electrodes exceeds the preset impedance value, the entire catheter is successfully attached.

[0132] In one embodiment, the judgment submodule 350 includes a first acquisition unit 353, a first calculation unit 354, a second acquisition unit 355, a second calculation unit 356, and a third comparison unit 357, wherein:

[0133] The first acquisition unit 353 is used to acquire the fourth impedance value between the second electrode and two adjacent electrodes before the catheter moves.

[0134] The first acquisition unit 353 is also used to acquire the fifth impedance value between the second electrode and two adjacent electrodes after the catheter is moved;

[0135] The first calculation unit 354 is used to calculate the second difference between the fourth impedance value and the corresponding fifth impedance value;

[0136] The second acquisition unit 355 is used to acquire the travel distance of the catheter;

[0137] The second calculation unit 356 is used to calculate the ratio of each second difference to the moving distance;

[0138] The third comparison unit 357 determines that the catheter has been successfully attached if the ratio is greater than the corresponding preset value.

[0139] In one embodiment, an impedance measurement system for a multi-electrode ablation catheter includes a multi-electrode ablation catheter and an impedance measurement device, wherein:

[0140] The multi-electrode ablation catheter is connected to an impedance measuring device. The impedance measuring device, the tip electrode of the multi-electrode ablation catheter, the tissue, the blood, and the reference electrode constitute an impedance measuring circuit. The reference electrode is either an external electrode patch or an electrode in the middle section of the multi-electrode ablation catheter.

[0141] The impedance measuring device applies a driving signal to the multi-electrode ablation catheter.

[0142] The impedance measuring device uses any of the above methods to determine the contact status of the multi-electrode ablation catheter.

[0143] It should be noted that any of the devices for detecting catheter contact status in this invention and the methods for detecting catheter contact status are based on the same technical concept, and the technical effects they bring are the same as those in the aforementioned method embodiments of this invention. For details, please refer to the description in the method embodiments of this invention, which will not be repeated here.

[0144] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting catheter affixation status, characterized in that, include: Measure the first impedance value, which is the impedance value of each electrode in the catheter; Measure the second impedance value, which is the impedance value between any two electrodes in the catheter; Determining whether the catheter has been properly attached based on the first impedance value and the second impedance value includes: The electrode with the smallest impedance value is identified as the first electrode, which is the electrode furthest from the tissue. Obtain the third impedance value between the first electrode and any other electrode; Calculate the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values; When the first difference is the largest, the second electrode is selected, which is the electrode closest to the tissue. The second electrode is used to determine whether the catheter has been properly attached.

2. The method for detecting catheter affixation status according to claim 1, characterized in that, The step of determining whether the catheter has been successfully attached based on the second electrode includes: If the first impedance value corresponding to the second electrode exceeds the preset impedance value, it is determined that the catheter is in contact with the tissue. Determine whether the first impedance value corresponding to the other electrodes exceeds the preset impedance value; If the determination is yes, then the entire catheter is successfully attached.

3. The method for detecting catheter affixation status according to claim 1, characterized in that, The step of determining whether the catheter has been successfully attached based on the second electrode includes: Obtain the fourth impedance value between the second electrode and the two adjacent electrodes before the catheter is moved; Obtain the fifth impedance value between the second electrode and the two adjacent electrodes after the catheter is moved; Calculate the second difference between the fourth impedance value and the corresponding fifth impedance value; Obtain the distance the catheter has traveled; Calculate the ratio of each of the second differences to the distance traveled; If all the ratios are greater than the corresponding preset values, it is determined that the catheter has been successfully attached.

4. The method for detecting catheter affixation status according to claim 1, characterized in that, The first impedance value is calculated using the following formula: ； in, The first impedance value is given by 'a', where 'a' is the weighting factor determined by the distance between the electrode and the target tissue. For blood resistance, This refers to tissue impedance.

5. A device for detecting the contact state of a catheter, characterized in that, include: The first measurement module is used to measure a first impedance value, wherein the first impedance value is the impedance value of each electrode in the catheter; The second measurement module is used to measure the second impedance value, which is the impedance value between any two electrodes in the catheter. The judgment module is used to determine whether the catheter has been properly attached based on the first impedance value and the second impedance value; The judgment module includes: The first selection submodule is used to determine the electrode with the smallest impedance value as the first electrode, and the first electrode is the electrode farthest from the tissue. The acquisition submodule is used to acquire the third impedance value between the first electrode and any other electrode. The first calculation submodule is used to calculate the first difference between the first impedance value corresponding to the first electrode and each of the third impedance values; The second selection submodule is used to select the second electrode when the first difference is the largest, wherein the second electrode is the electrode closest to the tissue. The judgment submodule is used to determine whether the catheter has been properly attached based on the second electrode.

6. The device for detecting catheter contact status according to claim 5, characterized in that, The judgment submodule includes: The first comparison unit is used to compare the first impedance value corresponding to the second electrode with a preset impedance value. If the first impedance value corresponding to the second electrode exceeds the preset impedance value, it is determined that the catheter is in contact with the tissue. The second comparison unit is used to compare the first impedance value corresponding to other electrodes with the preset impedance value. If the first impedance value corresponding to other electrodes exceeds the preset impedance value, the entire catheter is successfully attached.

7. The device for detecting catheter contact status according to claim 5, characterized in that, The judgment submodule includes: The first acquisition unit is used to acquire the fourth impedance value between the second electrode and two adjacent electrodes before the catheter moves; The first acquisition unit is further configured to acquire the fifth impedance value between the second electrode and two adjacent electrodes after the catheter is moved; The first calculation unit is used to calculate the second difference between the fourth impedance value and the corresponding fifth impedance value; The second acquisition unit is used to acquire the travel distance of the catheter; The second calculation unit is used to calculate the ratio of each of the second differences to the moving distance; In the third comparison unit, if all the ratios are greater than the corresponding preset values, it is determined that the catheter has been successfully attached.

8. An impedance measurement system for a multi-electrode ablation catheter, characterized in that, Includes multi-electrode ablation catheters and impedance measurement devices, among which: The multi-electrode ablation catheter is connected to the impedance measuring device. The impedance measuring device, the tip electrode of the multi-electrode ablation catheter, the tissue, the blood, and the reference electrode constitute an impedance measuring circuit. The reference electrode is an external electrode patch or an electrode in the middle section of the multi-electrode ablation catheter. The impedance measuring device applies a driving signal to the multi-electrode ablation catheter; The impedance measuring device uses the method for detecting catheter contact status as described in any one of claims 1-4 to determine the contact status of the multi-electrode ablation catheter.

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